1. The Field of the Invention
This invention relates to a system for enhancing the air within the surgical site during laser surgery. More particularly, the present invention is directed to a self-contained air enhancement system for evacuating the smoke plume created by use of the laser.
2. The Prior Art
The use of lasers in surgery has rapidly expanded in recent years. Initially, lasers were found to be particularly useful in very delicate surgery and surgery which requires extreme precision. As a result, the use of lasers in eye surgery and other types of microsurgery became well accepted during the 1970's. Indeed, many laser surgical devices incorporated a microscope into a laser source so that the area on which surgery was performed could be adequately and accurately viewed.
Since this early introduction of lasers into surgical procedures, they have found acceptance in more general areas of surgery outside of the microsurgical area. For example, lasers have currently found wide acceptance in the area of gynecological surgery.
With the rapid expansion in the use of lasers as surgical instruments, new problems have been encountered which are not generally encountered in conventional surgery. One serious problem is that of smoke produced during laser surgery. This smoke produced during laser surgery is generally referred to as a "laser plume."
Because of the high intensity of lasers used in laser surgery, tissue contacted by the laser may be rapidly and almost competely oxidized. The oxidized tissue typically results in a dense plume emitted from the surgical area. While the plume, consisting of oxidized tissue, is generally free of viable organic material, it has been found that the plume contains a variety of hydrocarbon compounds and carbon monoxide. While some smoke may be produced by conventional electric scalpels and similar devices, the intensity and volume of the smoke and pollutants produced in laser surgery presents a problem of much larger magnitude.
In one study which sought to determine the scope and intensity of the smoke produced during surgery, tissue was contacted by a laser under controlled conditions. It was found that the smoke and particulate matter produced amounted to almost 7.9 milligrams per cubic meter. This smoke density is approximately 52 times greater than the recommended density set by the governmental regulatory agencies.
In addition, the laser plume is known to contain particles of varying sizes. For example, one investigation found particles varying in size from under 0.4 microns to over 9.0 microns. Nevertheless, a large portion of the particles found in that study were under 1.1 microns in size; particles of this size are capable of being easily deposited in the alveoli of the lungs. Not only are particles of this size irritating to the respiratory system, but they may also be capable of causing serious respiratory disease. Moreover, repeated exposure to such particles can build within the lungs.
Several investigators have pointed out that repeated exposure to laser plumes may, for example, result in pneumonitis. In addition, it has been found that the laser plume is potentially mutagenic, and thus possibly carcinogenic. While much of the data in this area is still not definitive, it is clear that direct contact with laser plumes presents significant health risks, particularly to the medical personnel who are repeatedly exposed to such laser plumes.
Apart from the very significant problems resulting from inhaling the laser plume, laser plumes present additional difficulties. For example, it has been found that the laser plume may condense on the optical components of the laser itself, thereby causing pitting damage of the lenses. Similarly, the laser plume may enter mechanical devices and filters located in the operating room and clog or damage those devices and filters.
In order to combat the problems of damage to the laser itself by the laser plume, many modern conventional laser systems are equipped with air circulation systems. Typically, these systems drive a stream of air over the sensitive laser equipment and out toward the area being contacted by the laser beam. Thus, the laser plume is driven away from the laser equipment. However, it is found that this air flow forces the plume into the ambient air, thereby making it more difficult to control laser plume emissions.
Also of significance is the fact that the superheated steam component of the laser plume may cause serious burns in the event it comes into contact with the flesh. Of course, the primary danger in this regard is to the patient. Since the steam is produced by vaporizing body fluids, it is clear that there is a danger that those vaporized fluids may contact the surrounding tissue.
Nevertheless, in the event the steam leaves the localized surgical site, there is a danger that the heat associated with the steam may cause discomfort or otherwise provide an undesirable distraction to the surgeon or other operating room personnel. Thus, it is important that the steam produced in laser surgery be controlled and removed from the surgical site before exposure to the tissues surrounding the surgical site to operating room personnel.
Because of the potential harm caused by the laser plume, good practice dictates that the laser plume be controlled and removed from the surgical site before it contacts the patient, the laser equipment, or enters the ambient air. Thus, various devices have been developed for removing the laser plume; most of these devices involve the use of suction in some form.
The initial attempt to remove the laser plume was to simply use the operating room's built-in vacuum system to provide suction for removal of the plume. This solution, however, was found to be totally unsatisfactory because the building's vacuum system is not equipped to handle the dense hydrocarbon saturated smoke and associated particulates contained within the laser plume. The untreated laser plume has been found to clog and completely disable the entire hospital's vacuum system--a completely unacceptable result.
Because laser surgery often requires intense concentration on the part of the surgeon, as well as many other medical personnel, it is desirable to keep machinery and distractive noise in the operating room to a minimum. A significant disadvantage of the use of a portable vacuum system is the undesirable noise created in the operating room. Additionally, such a system can have significant resistance to air flow because of filters which easily become clogged with the particulate debris and other matter contained within the laser plume which is suctioned from the operating site. Unfortunately, a portable system has a limited filter capacity which renders their use ineffective because laser surgery creates greater wastes than result from more traditional surgical procedures.
This resistance to air flow significantly limits the flow rate of air traveling through the system, causing the laser plume removal process to be less efficient. Because the filters of conventional systems become clogged easily, they must be replaced more often to ensure that suction levels are adequate for removing the laser plume from the surgical site. This results in increased maintenance and cost, as well as possible disruption to the surgical procedure.
Studies have been performed concerning various methods for removing laser plumes. It has been found that if a suction device having appropriate air flow rates can be placed within approximately 1 centimeter of the source of the laser plume, then over 98% of the smoke and debris will be removed before it enters the ambient air. However, if the suction source with the same air flow is placed 2 centimeters from the source, only slightly over 50% of the smoke in the plume is removed. Thus, it will be appreciated that in the setting of the surgical theatre, it is important that laser plume removal systems be flexible and maneuverable, not bulky and hard to handle.
In view of the problems encountered in removing the laser plume from a surgical site, it would be a significant advancement in the art if a device could be provided which avoided the problems in the prior art identified above. Specifically, it would be an advancement in the art if a laser plume aspiration system could be provided which was inexpensive, easy to handle and flexible in use.
It would be a further advancement if such a system were compact, self-contained, and quiet in operation. It would also be a very significant advancement in the art if such a system could maintain a higher flow rate of air than conventional systems without the usual increased maintenance of having to change the filter more frequently. Such a device and aspiration system are disclosed and claimed herein.